U.S. patent application number 13/776187 was filed with the patent office on 2014-08-28 for fan assembly and fan wheel assemblies.
This patent application is currently assigned to Greenheck Fan Corporation. The applicant listed for this patent is GREENHECK FAN CORPORATION. Invention is credited to KYLE ANDREW BROWNELL, Shamus William Doran, Jared Clyde Wesenick.
Application Number | 20140241894 13/776187 |
Document ID | / |
Family ID | 51388344 |
Filed Date | 2014-08-28 |
United States Patent
Application |
20140241894 |
Kind Code |
A1 |
BROWNELL; KYLE ANDREW ; et
al. |
August 28, 2014 |
FAN ASSEMBLY AND FAN WHEEL ASSEMBLIES
Abstract
Fan assemblies, and in particular fan wheels and stator
assemblies for fan assemblies, are disclosed. In one embodiment,
the fan wheel includes a wheel back having an outer surface forming
one of a curved dome-shape and a truncated cone-shape. The fan
wheel may also include a plurality of fan blades radially spaced
about and mounted to the outer surface of the wheel back. In one
embodiment, each of the fan blades is formed from a segment of an
airfoil-shaped aluminum extrusion defining at least one internal
cavity. The fan blade first ends can be provided with a compound
cut profile with at least one curved cut such that the first end of
the blade is mounted flush to the wheel back outer surface. The
stator assembly can also be provided with a plurality of stator
blades formed from airfoil-shaped aluminum extrusion segments and
provided with compound cut profiles.
Inventors: |
BROWNELL; KYLE ANDREW;
(Schofield, WI) ; Doran; Shamus William; (Mosinee,
WI) ; Wesenick; Jared Clyde; (Wausau, WI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GREENHECK FAN CORPORATION |
Schofield |
WI |
US |
|
|
Assignee: |
Greenheck Fan Corporation
Schofield
WI
|
Family ID: |
51388344 |
Appl. No.: |
13/776187 |
Filed: |
February 25, 2013 |
Current U.S.
Class: |
416/223R |
Current CPC
Class: |
F04D 17/06 20130101;
H01F 38/14 20130101; F04D 19/002 20130101; Y02T 10/70 20130101;
F04D 29/388 20130101; F04D 29/281 20130101; F04D 29/30 20130101;
F04D 29/181 20130101; Y02T 90/14 20130101; Y02T 90/12 20130101;
F04D 29/242 20130101; H02J 7/0042 20130101; H01F 41/005 20130101;
F04D 29/384 20130101; F04D 29/2222 20130101; F04D 29/329 20130101;
F04D 23/005 20130101; F04D 29/326 20130101; F04D 29/544 20130101;
Y02T 10/7072 20130101; F04D 3/00 20130101; F04D 29/34 20130101;
F04D 29/183 20130101 |
Class at
Publication: |
416/223.R |
International
Class: |
F04D 29/18 20060101
F04D029/18 |
Claims
1. A mixed-flow type fan wheel for a fan assembly comprising: (a) a
wheel back having an outer surface forming one of a truncated
dome-shape and a truncated cone-shape; and (b) a plurality of fan
blades radially spaced about and mounted to the wheel back outer
surface: i. each of the fan blades having a first end and a second
end, the first end being mounted and oriented with respect to the
wheel back to define an interface contour projection at the wheel
back outer surface; ii. each of the fan blades being formed from a
segment of an airfoil-shaped aluminum extrusion defining at least
one internal cavity; iii. the fan blade first end having a first
compound cut profile with at least one curved cut, the compound cut
profile matching the first interface contour projection such that
the first end of the blade is mounted flush to the base outer
surface; (c) a wheel cone having a truncated cone shape defining an
inside surface to which the second end of each fan blade is
attached.
2. The mixed-flow type fan wheel of claim 1, wherein the second end
of each fan blade is mounted flush to the inside surface of the
wheel cone.
3. The mixed-flow type fan wheel of claim 2, wherein the fan blade
second ends have a second compound cut profile with at least one
curved cut.
4. The mixed-flow type fan wheel of claim 1, wherein the fan wheel
has six fan blades.
5. The mixed-flow type fan wheel of claim 1, wherein the fan blades
and the wheel cone are welded together.
6. The mixed-flow type fan wheel of claim 1, wherein the fan wheel
has been subjected to an aging process after the fan blade and the
base have been welded together.
7. The mixed-flow type fan wheel of claim 1, wherein the outer
surface of the wheel back has a curved dome-shape.
8. The mixed-flow type fan wheel of claim 1, wherein the outer
surface of the wheel back has a truncated cone-shape.
9. The mixed-flow type fan wheel of claim 1, wherein the compound
cut profile of each blade includes two curved cuts.
10. The mixed-flow type fan wheel of claim 1, wherein the first
compound cut profiled of each blade includes one curved cut and one
straight cut.
11. The axial-flow type fan wheel of claim 1, wherein the first end
of each blade forms a first angle of about 45 degrees with respect
to an axial centerline of the wheel hub.
12. The axial-flow type fan wheel of claim 1, wherein each of the
fan blades is twisted about a longitudinal axis of the fan
blade.
13. The axial-flow type fan wheel of claim 12, wherein each of the
fan blades is twisted such that the first end is at a second angle
of between about 5 degrees and about 45 degrees with respect to the
second end.
14. The axial-flow type fan wheel of claim 13, wherein the second
angle is about 10 degrees.
15. An axial-flow type fan wheel for a fan assembly comprising: (a)
a wheel hub having an outer surface forming one of a truncated
dome-shape and a truncated cone-shape; and (b) a plurality of fan
blades radially spaced about and mounted to the wheel hub outer
surface: i. each of the fan blades having a first end and a second
free end, the first end being mounted to the wheel hub and being
oriented with respect to the wheel back to define an interface
contour projection at the wheel back outer surface; ii. each of the
fan blades being formed from a segment of an airfoil-shaped
aluminum extrusion defining at least one internal cavity; iii. the
fan blade first end having a compound cut profile with at least one
curved cut, the compound cut profile matching the first interface
contour projection such that the first end of the blade is mounted
flush to the base outer surface.
16. The axial-flow type fan wheel of claim 15, wherein the fan
wheel has six fan blades.
17. The axial-flow type fan wheel of claim 15, wherein the first
end of each blade forms a first angle of about 45 degrees with
respect to an axial centerline of the wheel hub.
18. The axial-flow type fan wheel of claim 15, wherein each of the
fan blades is twisted about a longitudinal axis of the fan
blade.
19. The axial-flow type fan wheel of claim 16, wherein each of the
fan blades is twisted such that the first end is at a second angle
of between about 20 degrees and about 45 degrees with respect to
the second end.
20. The axial-flow type fan wheel of claim 17, wherein the second
angle is about 30 degrees.
21. The axial-flow type fan wheel of claim 15, wherein the fan
wheel has been subjected to an aging process after the fan blade
and the base have been welded together.
22. The axial-flow type fan wheel of claim 15, wherein the outer
surface of the wheel hub has a curved dome-shape.
23. The axial-flow type fan wheel of claim 15, wherein the outer
surface of the wheel hub has a truncated cone-shape.
24. The axial-flow type fan wheel of claim 15, wherein the compound
cut profile of each blade includes two curved cuts.
25. The axial-flow type fan wheel of claim 15, wherein the first
compound cut profiled of each blade includes one curved cut and one
straight cut.
26. A fan assembly comprising: (a) an outer housing; (b) an
electric drive motor; (c) a fan wheel disposed within the outer
housing and coupled to the electric drive motor, the fan wheel
comprising: i. a base having an outer surface forming one of a
truncated dome-shape and a truncated cone-shape; and ii. a
plurality of fan blades radially spaced about and mounted to the
base outer surface: 1. each of the fan blades having a first end
and a second end, the first end being mounted to the base and being
oriented with respect to the base to define an interface contour
projection at the wheel back outer surface; 2. each of the fan
blades being formed from a segment of an airfoil-shaped aluminum
extrusion defining at least one internal cavity; 3. the fan blade
first end having a compound cut profile with at least one curved
cut, the compound cut profile matching the first interface contour
projection such that the first end of the blade is mounted flush to
the base outer surface.
27. The fan assembly of claim 26, wherein the fan wheel is an
axial-flow type fan wheel and wherein the second end of each fan
blade is a free end and the base is a wheel hub.
28. The fan assembly of claim 26, wherein the fan wheel is a
mixed-flow type fan wheel and wherein the second end of each fan
blade is connected to a wheel cone and the base is a wheel
back.
29. The fan assembly of claim 26, wherein the fan wheel is a
mixed-flow type fan wheel and wherein the second end of each fan
blade is a free end that is axially spaced from an inlet structure
defining a wheel cone, the inlet structure being mounted to the
outer housing.
30. The fan assembly of claim 26, wherein the compound curved cut
is formed by a vertical machining center.
Description
BACKGROUND
[0001] Fan assemblies for providing airflow are known. In some
applications, fan assemblies include fan blades that are mounted to
a central hub or wheel back and have ends that match the profile of
the hub or wheel back. Where the fan blades are required to have a
three-dimensional airfoil cross-sectional shape, the blades are
often formed from laser or turret cut flat blank that has been
formed and welded or a casting process and then later joined to the
hub or wheel back. Improvements are desired.
SUMMARY
[0002] Fan assemblies for providing means for transporting air,
such as through a ducting system for a building supply, exhaust, or
return air system are disclosed. In one embodiment, the fan
assembly includes a mixed-flow type fan wheel while in another
embodiment the fan assembly includes an axial-flow type fan
propeller. As shown and described herein, each of the fan
assemblies include a generally cylindrical outer housing having an
outer surface and an inner surface. A stator assembly may also be
provided that serves to straighten airflow and to support an
electric drive motor that is coupled to the fan wheel.
[0003] In one embodiment, the fan wheel includes a wheel back
having an outer surface forming one of a curved dome-shape and a
truncated cone-shape. The fan wheel may also include a plurality of
fan blades radially spaced about and mounted to the outer surface
of the wheel back. Each of the fan blades can be configured to have
a first end mounted to the wheel back and can be oriented with
respect to the wheel back to define an interface contour projection
at the wheel back outer surface. In one embodiment, each of the fan
blades is formed from a segment of an airfoil-shaped aluminum
extrusion defining at least one internal cavity. The fan blade
first ends can be provided with a compound cut profile with at
least one curved cut line wherein the compound cut profile matches
the first interface contour projection such that the first end of
the blade is mounted flush to the wheel back outer surface.
[0004] In one embodiment the stator assembly includes a generally
cylindrical inner housing having an outer surface and a motor
support flange connected to the inner housing. The stator may be
provided with a plurality of radially spaced stator blades
extending from the inner housing to the inner surface of the fan
assembly. The stator blades can be oriented such that air leaving
the fan wheel is straightened to a certain extent within the
housing before leaving the fan assembly. In one embodiment, each of
the stator blades has a first end mounted to the inner housing
outer surface and being oriented with respect to the inner housing
to define an interface contour projection at the inner housing
outer surface. Each of the stator blades is formed from a segment
of an airfoil-shaped aluminum extrusion defining at least one
internal cavity. The stator blade first end can be configured with
a compound cut profile with at least one curved cut line such that
the compound cut profile matches the second interface contour
projection thereby allowing the first end of the stator blade is
mounted flush to the inner housing outer surface.
[0005] Method for making fan assemblies, and in particular fan
wheels and stator assemblies, are also disclosed.
DESCRIPTION OF THE DRAWINGS
[0006] Non-limiting and non-exhaustive embodiments are described
with reference to the following figures, which are not necessarily
drawn to scale, wherein like reference numerals refer to like parts
throughout the various views unless otherwise specified.
[0007] FIG. 1 is an exploded perspective view of a first embodiment
of a fan assembly having features that are examples of aspects in
accordance with the principles of the present disclosure.
[0008] FIG. 2 is a perspective view of a mixed-flow fan wheel
usable in the fan assembly shown in FIG. 1.
[0009] FIG. 3 is a perspective view of a portion of the fan wheel
shown in FIG. 2, with the wheel cone and center hub removed.
[0010] FIG. 4 is a front view of the fan wheel shown in FIG. 2.
[0011] FIG. 5 is a front view of a portion of the fan wheel shown
in FIG. 2, with the wheel cone and center hub removed.
[0012] FIG. 6 is a side view of the fan wheel shown in FIG. 2.
[0013] FIG. 7 is a side view of a portion of the fan wheel shown in
FIG. 2, with the wheel cone and center hub removed.
[0014] FIG. 8 is a perspective view of a fan wheel back usable with
the fan wheel shown in FIG. 2.
[0015] FIG. 9 is a side view of a fan wheel back usable with the
fan wheel shown in FIG. 2.
[0016] FIG. 10 is a top view of a fan wheel back usable with the
fan wheel shown in FIG. 2.
[0017] FIG. 11 is a top view of a fan blade usable with the fan
wheel shown in FIG. 2.
[0018] FIG. 12 is a bottom view of the fan blade shown in FIG.
11.
[0019] FIG. 13 is a front view from the leading edge of the fan
blade shown in FIG. 11.
[0020] FIG. 14 is a rear view from the trailing edge of the fan
blade shown in FIG. 11.
[0021] FIG. 15 is a side edge view of the fan blade shown in FIG.
11.
[0022] FIG. 16 is a perspective view of a second embodiment of a
mixed-flow fan wheel usable in the fan assembly of FIG. 1 and
having features that are examples of aspects in accordance with the
principles of the present disclosure.
[0023] FIG. 17 is a perspective view of a portion of the fan wheel
shown in FIG. 16 with the wheel cone and center hub removed.
[0024] FIG. 18 is a top view of the fan wheel shown in FIG. 16.
[0025] FIG. 19 is a side view of the fan wheel shown in FIG.
16.
[0026] FIG. 20 is a perspective view of a third embodiment of a
mixed-flow fan wheel usable in the fan assembly of FIG. 1 and
having features that are examples of aspects in accordance with the
principles of the present disclosure.
[0027] FIG. 21 is a top view of the fan wheel shown in FIG. 20.
[0028] FIG. 22 is a side view of the fan wheel shown in FIG.
20.
[0029] FIG. 23 is a front perspective view of a portion of the fan
wheel shown in FIG. 20.
[0030] FIG. 24 is a side view of a portion of the fan wheel shown
in FIG. 20.
[0031] FIG. 25 is a top view of a portion of the fan wheel shown in
FIG. 20.
[0032] FIG. 26 is a perspective exploded view of a third embodiment
of a mixed-flow fan wheel and combined wheel cone and inlet cone
having features that are examples of aspects in accordance with the
principles of the present disclosure.
[0033] FIG. 27 is a perspective view of a combined wheel cone and
bell cone usable with the fan assembly of FIG. 26.
[0034] FIG. 28 is a top view of the combined wheel cone and bell
cone of FIG. 26.
[0035] FIG. 29 is a side view of the combined wheel cone and bell
cone of FIG. 26.
[0036] FIG. 30 is a perspective view of a stator assembly usable
with the fan assembly shown in FIG. 1.
[0037] FIG. 31 is a front view of the stator assembly shown in FIG.
30.
[0038] FIG. 32 is a side view of the stator assembly shown in FIG.
30.
[0039] FIG. 33 is a side view of a portion of the stator assembly
shown in FIG. 30.
[0040] FIG. 34 is a top view of a stator blade usable with the
stator assembly shown in FIG. 30.
[0041] FIG. 35 is a bottom view of the stator blade shown in FIG.
34.
[0042] FIG. 36 is a front view from the leading edge of the stator
blade shown in FIG. 34.
[0043] FIG. 37 is a rear view from the trailing edge of the stator
blade shown in FIG. 34.
[0044] FIG. 38 is a side edge view of the stator blade shown in
FIG. 34.
[0045] FIG. 39 is a cross-sectional schematic view of the fan
assembly of FIG. 1 at the location of the stator assembly shown in
FIG. 30 with motor wiring routed through a stator blade.
[0046] FIG. 40 is an exploded perspective view of a second
embodiment of a fan assembly having features that are examples of
aspects in accordance with the principles of the present
disclosure.
[0047] FIG. 41 is a perspective view of third embodiment of a fan
assembly having features that are examples of aspects in accordance
with the principles of the present disclosure.
[0048] FIG. 42 is a front perspective view of a fan wheel usable
with the fan assembly shown in FIG. 41.
[0049] FIG. 43 is a rear perspective view of a fan wheel usable
with the fan assembly shown in FIG. 41.
[0050] FIG. 44 is a top view of the fan wheel shown in FIG. 41.
[0051] FIG. 45 is a bottom view of the fan wheel shown in FIG.
41.
[0052] FIG. 46 is a side view of the fan wheel shown in FIG.
41.
[0053] FIG. 47 is a front perspective view of a portion of the fan
wheel shown in FIG. 41.
[0054] FIG. 48 is a side view of a portion of the fan wheel shown
in FIG. 41.
[0055] FIG. 49 is a top view of a portion of the fan wheel shown in
FIG. 41.
[0056] FIG. 50 is a perspective view of a second embodiment of an
axial-flow fan wheel having features that are examples of aspects
in accordance with the principles of the present disclosure.
[0057] FIG. 51 is a top view of the fan wheel shown in FIG. 50.
[0058] FIG. 52 is a side view of the fan wheel shown in FIG.
50.
[0059] FIG. 53 is a top view of a fan blade usable with the fan
wheels shown in FIGS. 41 and 50.
[0060] FIG. 54 is a bottom view of the fan blade shown in FIG.
53
[0061] FIG. 55 is a front view from the leading edge of the fan
blade shown in FIG. 53.
[0062] FIG. 56 is a rear view from the trailing edge of the fan
blade shown in FIG. 53.
[0063] FIG. 57 is a flow chart showing a process for creating a fan
wheel assembly.
[0064] FIG. 58 is a flow chart showing a process for creating a fan
assembly outer housing.
[0065] FIG. 59 is a flow chart showing a process for creating a fan
assembly stator housing.
[0066] FIG. 60 is a flow chart showing a process for creating a
stator assembly.
[0067] FIG. 61 is a flow chart showing a process for creating a fan
assembly having a mixed-flow fan with a separate wheel cone.
DETAILED DESCRIPTION
[0068] Various embodiments will be described in detail with
reference to the drawings, wherein like reference numerals
represent like parts and assemblies throughout the several views.
Reference to various embodiments does not limit the scope of the
claims attached hereto. Additionally, any examples set forth in
this specification are not intended to be limiting and merely set
forth some of the many possible embodiments for the appended
claims.
Mixed Flow Fan Assembly
General Description
[0069] Referring now to FIG. 1, an example fan assembly 10 is
shown. Fan assembly 10 is for providing means for transporting air,
such as through a ducting system (not shown) relating to a building
heating, ventilation, and air conditioning system. As shown, fan
assembly 10 includes a generally cylindrical outer housing 20
defining an outer surface 20a and an inner surface 20b. Housing 20
is also shown as being provided with a first flange 22 and a second
flange 24. The first and second flanges 22, 24 are for allowing the
fan assembly 10 to be connected to the ducting system or other
equipment. Flange 22 is also shown as being configured to accept a
bell inlet 30 which serves the purpose of guiding air into a fan
wheel 40 of the fan assembly 10. In the embodiment shown, the
housing 20 is formed by rolling and the ends of the sheet from
which the housing 20 is formed joined together at a seam line 26.
In one embodiment, the housing 20 ends are joined together at seam
line 26 by a welding process, for example by plasma arc welding.
Plasma arc welding of the seam line 26 is preferable because this
type of welding can be performed such that it does not
significantly damage the galvanized protective coating in the area
of the weld. Additionally, this type of welding can be done to
minimize the overall height of the weld which reduces or eliminates
the need to grind on the outer tube prior to forming the flange on
the welded tube. By minimizing the amount of galvanized coating
that is damaged in the welding process, the tube can be
manufactured with minimal or no additional post processing to
protect the weld area using paint or other protective coatings.
[0070] The fan wheel 40 is mounted to and driven by an electric
drive motor 60 via a shaft 62 provided on the motor 60. The fan
wheel 40 may be provided with a center hub or coupling mechanism 46
to accept a keyed or splined motor shaft 62 such that rotation of
the motor shaft 62 effectuates rotation of the fan wheel 40. As the
fan wheel 40 rotates, air is directed from an inlet end 40a to an
outlet end 40b.
[0071] As shown, the fan wheel 40 includes a plurality of
airfoil-shaped radially disposed extruded fan blades 70. The fan
blades 70 extend from an outer surface 42a of a base, such as a
wheel back 42, to an inner surface 44b of a wheel cone 44 having
the shape of a truncated cone. In operation, the fan blades 70 and
the wheel cone 44 operates in conjunction to force or direct the
generated airflow from the inlet end 40a of the fan wheel towards
the outlet end 40b of the fan wheel. This type of configuration is
conventionally known as a "mixed flow" type fan which shares
characteristics of both centrifugal and axial type fans. As shown,
fan wheel 40 is provided with six fan blades 70. However, it should
be understood that more or fewer fan blades are possible, such as
four or five fan blades or up to twelve fan blades. The fan wheel
40 and constituent components are discussed in further detail in
later sections of this specification.
[0072] The fan assembly 10 is also shown as being provided with a
stator assembly 50 which serves the purpose of supporting and
housing the electric drive motor 60 via a support flange 52 and
inner housing 54, respectively. As shown, the inner housing 54 is
generally cylindrical and has an outer surface 54a and an inner
surface 54b. In the embodiment shown, the inner housing 54 also has
a notch 56 to allow for a portion of the motor 60, such as a
junction box, to extend beyond the inner housing 54.
[0073] The stator assembly 50 also operates to straighten the
airflow after the air has passed through the fan wheel 40. This is
accomplished via a plurality of radially disposed airfoil-shaped
extruded stator blades 80 extending from the outer surface 54a of
the inner housing 54 to the inner surface 20b of the outer housing
20. The fan wheel is discussed in further detail in other parts of
the specification. By providing a covering over the motor 60, the
stator assembly also operates to smoothly guide the airflow from
the fan wheel 40 smoothly around the motor 60. The stator assembly
50 is discussed in further detail in later sections of this
specification.
Mixed Flow Fan Wheel Assembly
First Embodiment
[0074] Referring to FIGS. 2-15, details of the fan wheel assembly
40 are further shown. It is noted that the wheel cone 44 of the fan
wheel 40 is not shown in FIGS. 3, 5, and 7 for the purpose of
providing further clarity. It is further noted that FIGS. 8-10 show
only the wheel back 42 and that FIGS. 11-15 show only the fan wheel
blades 70.
[0075] As stated previously, fan wheel assembly 40 is provided with
a wheel back 42. The wheel back 42 has a base portion 42c and a
flattened top portion 42b. As shown, the center hub or coupling
mechanism 46 extends between the base portion 42a and the top
portion 42b. As can be most easily seen at FIG. 9, the outer
surface 42a of the wheel back 42 is curved or domed-shaped when
viewed from the side such that the outer surface 42a forms a
portion of a dome. The curvature of the outside surface 42a may
have either a constant radius or a variable radius. It is noted
that profile of the outer surface 42a could be straight when viewed
from the side such that outer surface 42a forms a portion of a cone
or a cylinder. Although the top portion is shown as being
flattened, the top portion could be rounded or angled to match the
profile of the outer surface 42a such that a more continuous or
fully continuous dome or cone shape is produced. Thus, wheel back
outer surface 42a may have a dome-shape, a truncated dome-shape, a
cone-shape, a truncated cone-shape, or a cylindrical shape. It is
also noted that, when viewed from above as shown in FIG. 10, both
the base portion 42c and the top portion 42b are circular in shape,
and thus have a rounded shape in this regard.
[0076] Referring to FIGS. 11-15, an example fan blade 70 is shown
in greater detail. In one embodiment, the fan blade 70 is formed
from a segment of an airfoil-shaped, double-walled extrusion, and
in particular a segment of an aluminum extrusion. Other types of
materials may be used instead of aluminum for the extruded fan
blade 70. As shown, each fan blade 70 has a leading edge 71 and a
trailing edge 72, between which a chord length CL is defined. The
leading and trailing edges 71, 72 extend between a first end 73 and
a second end 74 of the fan blade 70. As shown, the fan blade 70 has
a top surface 75 and a bottom surface 76 separated by an internal
hollow cavity 77. The presence of the cavity 77 results in the
material forming the top and bottom surfaces 75, 76 having a
material thickness t for the majority of the chord length of the
blade 70. It is noted that the blade 70 can be formed with more or
fewer hollow cavities without departing from the concepts presented
herein. Also, the top and bottom surfaces 75, 76 together define an
overall blade height H.
[0077] Referring to FIG. 15, it can be seen that the fan blade 70
further has a structural support post 78 that subdivides cavity 77
into a first sub-cavity 77a and a second sub-cavity 77b. As shown,
the post 78 has an angle .alpha.1 with respect to axis Z. FIG. 15
also shows that the top surface has an initial angle .alpha.2 from
the trailing edge 72 while the bottom surface has an initial angle
.alpha.3 from the trailing edge. In the particular embodiment
shown, H is about 1.1 inches, t is about 0.1 inches, CL is about
9.1 inches, .alpha.1 is about 21 degrees, .alpha.2 is about 73
degrees, and .alpha.3 is about 69 degrees. However, one skilled in
the art upon learning of the disclosure herein will understand that
many other fan blade 70 dimensions and shapes are possible. For
example, the dimensions described herein are for a particular size
and many larger and smaller sizes can be scaled from the disclosed
embodiments.
[0078] When a fan blade 70 is positioned and oriented as desired
with respect to wheel back 42, a three-dimensional fan blade
interface contour projection 48 can be defined on the outer surface
42a of the wheel back 42. An example contour projection 48 for one
of the blades 70 is shown at FIGS. 8-10. In one aspect, the contour
projection 48 can be visualized as being the outline that could be
drawn onto the wheel back outer surface 42a around an intersecting
fan blade if it were possible to pass the end of the fan blade 70
through the outer surface 42a with the fan blade 70 placed in the
desired orientation. Thus, the shape of the contour projection 48
is defined by the position and orientation of the blade 70 with
respect to the back 42, and also by the shape of the outer surface
42a of the wheel back itself.
[0079] The fan blade orientation is defined by the rotation of the
fan blade 70 about the blade's 70 longitudinal axis L, transverse
axis T, and centerline axis Z with respect to the wheel back 42.
Axes L, T, and Z are shown at FIG. 11. The rotation of the blade
about the longitudinal axis L operates to define an angle .alpha.4,
such as a blade pitch angle, as shown at FIG. 9. The rotation of
the blade 70 also operates to define an angle .alpha.5 of the fan
blade 70 with respect to the back 42, as shown in FIG. 7. The
rotation of the blade 70 also operates to define an angle .alpha.6
of the fan blade 70 with respect to the back 42, as shown in FIG.
5. As shown, .alpha.4 is about 24 degrees, .alpha.5 is about 37
degrees, and .alpha.6 is about 20 degrees although many other
specific orientations are possible.
[0080] In order for the first end 73 of the fan blade 70 to be
mounted flush to the wheel back outer surface 42a, meaning that
generally no significant gaps are present between the blade
material at the first end 73 and the outer surface 42a, the first
end 73 must match the blade interface projection contour 48. As the
fan blade 70 is formed from an extrusion, as opposed to being
formed in a casting process, the first end 73 must be cut to match
the projection contour 48. Where the outer surface 42a has a
dome-shape and the blade first end 73 has a double-wall airfoil
shape, the resulting cut required to match the projection contour
48 must be a compound cut that is curved in two directions. For
example, FIG. 11 shows a curved cut line in a direction from the
leading edge 71 to the trailing edge 72 of the fan blade 70 while
FIG. 13 shows a curved cut line in a direction from the top surface
75 to the bottom surface 76 to the fan blade 70. Due to the
complexity of the shape of the projection contour 48, this type of
compound curved cut cannot be readily accomplished with a cutting
machine having a flat blade, a rotating blade, a water jet cutter,
or a laser cutting device. Therefore, the first end 73 must be cut
by other processes, such as the use of a vertical machining center.
Such an approach can involve at least two different types of
cutting tools and CNC control of the cutting head and the work
table to create an accurate profile. Where the outer surface 42a
has a conical or cylindrical shape, instead of a dome shape, the
first end 73 of a double-wall airfoil fan blade 70 will still
require a compound cut with a curved cut line from the leading to
trailing edge 71, 72. However, the cut from the top surface 75 to
the bottom surface 76 will be a straight cut line instead of a
curved cut.
[0081] The second end 74 of the fan blade 70 must also be cut in
order to match the inside surface of the wheel cone 44. In the same
manner that a projection contour 48 can be defined at the wheel
back outer surface 42a, a second three-dimensional fan blade
interface contour projection 49 can be defined at the wheel cone
inner surface 44b. Accordingly, the description of the concepts
regarding the shape and formation of the cut at the first end 73 is
equally applicable to, and hereby incorporated by reference into,
the description for the shape and formation of the cut at the
second end 74. In the embodiment shown, the wheel cone 44 is a
portion of a cone and therefore has a straight profile shape.
Accordingly, where the blade second end 74 has a double-wall
airfoil shape, the resulting cut required to match the projection
contour 49 must be a compound cut that is curved in one direction
and straight in another direction. For example, FIGS. 11-12 show a
curved cut from the leading edge 71 to the trailing edge 72 of the
fan blade 70 while FIGS. 13-14 show a straight cut from the top
surface 75 to the bottom surface 76 to the fan blade 70. Where the
inlet 44 has a curved profile, then the compound cut of the second
end 74 would have two curved cuts rather than a single curved
cut.
[0082] Once each blade 70 has been cut at the first and second ends
73, 74, the blades 70 can then be attached to the wheel back 42. In
one embodiment, the wheel back 42 and blades 70 are metal, such as
aluminum, and joined together by a welding process. In one
embodiment, all of the components are manufactured from a soft
aluminum, such as series 6000 aluminum. In one embodiment, 6063
designated aluminum is utilized. In one embodiment, 6061 designated
aluminum is utilized. These components would include the wheel back
42, the fins, the wheel cone 44 and the machined hub or any
combination of the above. Once welded together these components can
be subjected to a tempering process, such as heating, cooling, hot
working, cold working, naturally aging, artificially aging,
stretching, and/or stretching to increase the strength of the
material. In one embodiment, the components are subjected to a
tempering process to result in a temper designation of T5 while in
another embodiment, tempered to a T6 temper designation, for
example to result in 6063-T5 or 6063-T6 aluminum, respectively.
This approach is advantageous because the entire structure can be
tempered to have near uniform strength whereas structures that are
formed from tempered aluminum can lose significant strength at the
weld locations due to complete or partial annealing caused by
heating in certain welding process.
Mixed Flow Fan Wheel Assembly
Second Embodiment
[0083] Referring to FIGS. 16-19, a second embodiment of a
mixed-flow fan wheel 140 is shown that can be used in the fan
assembly 10 shown in FIG. 1. As many of the concepts and features
are similar to the first embodiment shown in FIGS. 1-15, the
description for the first embodiment, and all other embodiments
presented herein relating to fan wheels, is hereby incorporated by
reference for the second embodiment. Where like or similar features
or elements are shown, corresponding or like reference numbers will
be used where possible (e.g. 170 instead of 70). Referring to FIG.
17, it can be seen that each blade 170 is twisted about a
longitudinal axis L of the blade such that a chord line CL1 drawn
at the first blade end 173 is disposed at an angle .alpha.8 with
respect to a chord line CL2 drawn at the second end 174. As used
herein, chord lines CL1 and Cl2 are each defined as a line
extending in a direction from the leading edge 171 to the trailing
edge 172 of the blade 174 at a given location along the extension
of the blade 174. In the embodiment shown, the angle .alpha.8 is
between about 5 degrees and about 45 degrees, for example about 10
degrees. In such a configuration, the trailing edge 172 of the
blade 170 at the second end 174 is closer to the longitudinal axis
X of the fan wheel than is the trailing edge 172 at the first end
173 which allows for increased efficiency of the fan wheel.
Mixed Flow Fan Wheel Assembly
Third Embodiment
[0084] Referring to FIGS. 20-25, a third embodiment of a mixed-flow
fan wheel 40' without the wheel cone 44 shown is presented. As many
of the concepts and features are similar to the first and second
embodiments shown in FIGS. 1-19, the description for the first and
second embodiments, and all other embodiments presented herein
relating to fan wheels, is hereby incorporated by reference for the
third embodiment. Where like or similar features or elements are
shown, corresponding or like reference numbers will be used where
possible (e.g. 270 instead of 70). The primary difference of the
third embodiment 240 from the first and second embodiments 40, 140
is that the wheel back 242 of the third embodiment 240 is provided
in conical form instead of having a dome shape. Because the shape
of the wheel back 242 is conical, the blade interface projection
contour shape is necessarily changed. Thus, a different cut at the
first end 273 of the blade 270 is required. Similar to the first
and second embodiments 40, 140, the cut at the first end 273 would
still be a compound cut with a curved cut line extending between
leading and trailing edges 271, 272. However, the cut line
extending from the top surface 75 to the bottom surface 76 would be
a straight cut line instead of having a curved direction. It is
noted that although straight blades 270 are shown for the third
embodiment 240, the blades could be twisted in the same manner as
presented for the second embodiment 140 to result in a fan wheel
with twisted blades and a conical wheel back.
Mixed Flow Fan Wheel Assembly
Fourth Embodiment
[0085] Referring to FIGS. 26-29, a fourth embodiment of a fan wheel
340 is presented along with an inlet structure 331 that combines
the bell inlet 330 and wheel cone 344. As many of the concepts and
features are similar to the first to third embodiments shown in
FIGS. 1-25, the description for the first to third embodiments, and
all other embodiments presented herein relating to fan wheels, is
hereby incorporated by reference for the fourth embodiment 340.
Where like or similar features or elements are shown, corresponding
or like reference numbers will be used where possible (e.g. 370
instead of 70).
[0086] Referring to FIG. 45, the fan wheel 340 is shown in an
exploded view and is provided with a conical base or wheel back 342
and straight blades 370. However, and as mentioned previously for
other embodiments, fan wheel 340 may be provided with twisted
blades and/or a dome shaped wheel back.
[0087] In contrast to the first to third embodiments, each of the
fan blades 370 of the fourth embodiment of the fan wheel 340 has a
free second end 374 rather than being directly attached to a wheel
cone 344. As configured, the wheel cone 344 and the fan wheel 340
are aligned along a common central axis X and spaced apart a
distance D along the axis X. Referring to FIG. 29, distance D is
defined as the distance between the second end 374 of the blade 370
and the inside surface 344b of the wheel cone 344. As such, the
blade second ends 374 are received within the wheel cone portion
344, but are not in contact with the inner surface 344b of the
wheel cone portion 344. In one embodiment, distance D is from about
1 millimeter to about 3 millimeters. In order to minimize distance
D as much as possible, it is preferred that the blades 370 are cut
to have a contour cut profile matching the inside surface 344b at
the second ends for maximum efficiency, in the same manner as
already described for the first embodiment.
[0088] As shown, the inlet structure 331 is a unitary structure
having an air inlet 331a and an outlet 331b. The inlet structure
331 incorporates the wheel cone 344 and the bell inlet 330. It is
noted that the inlet structure may be formed from a single piece of
material or from multiple pieces of material. For example, the
wheel cone 344 could be formed from a first sheet of material and
the bell inlet 330 could be formed from a second sheet of material
wherein the formed wheel cone 344 and bell inlet 330 are joined
together via welding, mechanical fasteners, or other joining means
known in the art. In the embodiment shown, the inlet structure 331
is formed from a single galvanized sheet in a rolling process to
define a bell inlet portion 332 and an inlet cone portion 344.
Other suitable materials are cold rolled steel, stainless steel,
and aluminum sheet.
[0089] As shown, the bell inlet portion 330 includes a flange
portion 332, a narrowing portion 330a, and a generally cylindrical
portion 330b. The narrowing portion 330a can be formed by a curved
radius that transitions the inlet 331a of the inlet structure 331
between a first diameter d1 defined by the inside of the flange
portion 332 and a second diameter d2 defined by generally
cylindrical portion 330b. As shown, the wheel cone portion 334
towards the inlet end 331a has a diameter d2 and expands to a
diameter d3 at the outlet 331b of the inlet structure 331. As
shown, the inlet cone portion 344 is presented in the shape of a
truncated cone. However, the inlet cone portion 344 could be
provided with a curved or truncated dome shape. As most easily seen
at FIG. 29, diameters d1 and d3 are both greater than diameter d2.
In one embodiment, diameters d1 and d3 are generally equal. Still
referring to FIG. 29, it can be seen that the bell inlet portion
330 has a first height H1 and the wheel cone portion 344 has a
second height H2. As shown, first height H1 is greater than second
height H2. As shown in FIG. 29, the following are approximate
dimensions: d3=27.8 inches, d1=27.9 inches, d2=19.7 inches, H1=9.2
inches and H2=6 inches. In general, d1 is close to the same
dimension as d3 in some applications, for example, d1 is within
about 5% of d3. In one embodiment, d3 is within about 1% of d1 and
d2 is within about 30% of d1.
[0090] As a result of the rolling process, a lead edge 334 of the
sheet is joined with a trailing edge 336 of the sheet to form a
seam line 338. The lead edge 334 may be joined to the trailing edge
336 at the location of the seam line 338 by a welding process, for
example by plasma arc welding. Plasma arc welding of the seam line
338 is preferable because this type of welding can be performed
such that that it does not significantly damage the galvanized
protective coating in the area of the weld. Additionally, this type
of welding can be done to minimize the overall height of the weld
which reduces or eliminates the need to grind on the outer tube
prior to forming the flange on the welded tube. By minimizing the
amount of galvanized coating that is damaged in the welding
process, the tube can be manufactured with minimal or no additional
post processing to protect the weld area using paint or other
protective coatings. It is noted that at least the wheel cone
portion 344 should be as round as possible such that the gap
between the blade second ends 374 and the inner wheel cone surface
344b (i.e. distance D) is as small as possible.
[0091] In one embodiment, the inlet structure 331 is attached to
the fan assembly 10 via flange 332, which is shown as having a
plurality of mounting holes 332a. The flange 332 is aligned and
attached to the first flange 22 of the housing 20 such that
mounting holes 22a provided on the first flange 22 are aligned with
the mounting holes 332a on flange 332. Mechanical fasteners (not
shown) can be used to secure the flanges together, and to ensure
alignment of the inlet structure 331 with respect to the fan wheel
340. In one embodiment, the inlet structure 331 is attached to the
fan assembly by a TOG-L-LOC.RTM. connection or similar connection
method, or by welding.
Stator Assembly
[0092] Referring to FIGS. 30-39, the stator assembly 50 is shown in
greater detail. It is noted that FIGS. 19-22 show an example of one
of the stator blades 80 shown in FIGS. 16-18 while FIG. 19 shows
only the inner housing tube 54 of the stator assembly. As stated
previously, the stator assembly 50 serves the functions of
supporting the motor 60, guiding the airflow from the fan wheel 40
smoothly around the motor 60, and straightening the airflow leaving
the fan wheel 40.
[0093] As stated previously, stator assembly 40 is provided with an
inner housing tube 54 that is generally cylindrical in shape
although other shapes could be utilized. The inner housing 54 is
configured to accept the mounting flange 52 having a central
aperture 52b which may be integral to the housing 54 or formed
separately and mechanically coupled to the inner housing 54, such
as by welding or mechanical fasteners. The mounting flange 52 is
provided with a number of mounting holes 52a that match
corresponding holes on the electric drive motor 60 such that bolts
may pass through the mounting flange 52 to support the motor 60.
The inner housing 54 may be configured to accept differently
configured mounting flanges to accommodate a particular motor 60 or
motor size that is to be used in the fan assembly 10. The notch 56
in the inner housing 54 is provided for those motor sizes having a
junction box that exceeds the inner diameter of the inner housing
such that the junction box can be accommodated and accessed. The
stator blades 80 of the stator assembly are radially spaced about
and connected to the inner housing 54. In the embodiment shown, 13
stator blades 80 are provided. However, more or fewer stator blades
80 may be used without departing from the concepts presented
herein.
[0094] Referring to FIGS. 20-24, an example stator blade 80 is
shown in greater detail. It is noted that many of the
aforementioned concepts described for the fan blade 70 are
applicable for the stator blade 80. Accordingly, the description
for the fan blade 70 is hereby incorporated by reference into the
description for the stator blade 80. In one embodiment, and
similarly to fan blade 70, the stator blade 80 is formed from a
segment of an airfoil-shaped, double-walled extrusion, and in
particular a segment of an aluminum extrusion. Other types of
materials may be used instead of aluminum for the extruded stator
blade 80. Also, the stator blade 80 and the fan blade 70 may be
formed from segments of the same extrusion.
[0095] As shown, each stator blade 80 has a leading edge 81 and a
trailing edge 82, between which a chord length CL2 is defined. The
leading and trailing edges 81, 82 extend between a first end 83 and
a second end 84 of the stator blade 80. As shown, the stator blade
80 has a top surface 85 and a bottom surface 86 separated by an
internal hollow cavity 87. The presence of the cavity 87 results in
the material forming the top and bottom surfaces 85, 86 having a
material thickness T2 for the majority of the chord length of the
blade 80. It is noted that the blade 80 can be formed with more or
fewer hollow cavities without departing from the concepts presented
herein. Also, the top and bottom surfaces 85, 86 together define an
overall blade height H2. The hollow cavities 87 in the stator
blades can also be used to run the motor electrical cabling or
wires 61 from the motor 60 to the outside of the housing 20, as
shown schematically in FIG. 39. Where this type of routing is
utilized, the notch or cut-out 56 in the inner tube 54 is not
necessarily needed. Also, this type of routing also eliminates the
need for a conduit box in the airstream thus improving the
performance of the fan, for example a 2% improvement in overall fan
efficiency.
[0096] Referring to FIG. 38, it can be seen that the stator blade
80 further has a structural support post 88 that subdivides cavity
87 into a first sub-cavity 87a and a second sub-cavity 87b.
Additionally, the stator blade 80 is shown as being provided with
two anchor cavities 89. The anchor cavities 89 line up with
corresponding apertures 57 in the inner housing 54 as well as
apertures 47 in the outer fan housing 20, and are configured to
accept mounting screws to secure the stator blades 20. Thus, the
inner housing 50 is secured within the outer housing 20 by the
stator blades 80. Alternatively, the stator blades 80 could be
welded or otherwise secured to the inner housing and/or outer
housing 20.
[0097] In general, the stator blade 80 has a cross-sectional
profile similar to that shown for the fan blade 70. Thus, the
stator blade 80 has generally the same values for the angles
corresponding to .alpha.1, .alpha.2, and .alpha.3 shown for the fan
blade 70. In the particular embodiment shown, H2 is about 1.1
inches, T2 is about 0.1 inches, and CL2 is about 9.1 inches.
However, one skilled in the art upon learning of the disclosure
herein will understand that many other stator blade 80 dimensions
and shapes are possible.
[0098] When a stator blade 80 is positioned and oriented as desired
with respect to the inner housing 54, a three-dimensional fan blade
interface contour projection 58 can be defined on the outer surface
54a of the inner housing 54. An example contour projection 58 for
one of the blades 80 is shown at FIG. 33. In one aspect, the
contour projection 58 can be visualized as being the outline that
could be drawn onto the inner housing outer surface 54a around an
intersecting stator blade 80 if it were possible to pass the end of
the stator blade 80 through the outer surface 54a with the stator
blade 80 placed in the desired orientation. Thus, the shape of the
contour projection 58 is defined by the position and orientation of
the blade 80 with respect to the housing 54, and also by the shape
of the outer surface 54a of the housing itself.
[0099] The stator blade orientation is defined by the rotation of
the stator blade 80 about the blade's 80 longitudinal axis L2,
transverse axis T2, and centerline axis Z2 with respect to the
housing 54. Axes L2, T2, and Z2 are shown at FIG. 34. In the
embodiment shown, the stator blade 80 is oriented generally
orthogonally to the outer surface 54a such that the longitudinal
axis L2 is perpendicular to the outer housing surface 54a and the
transverse axis T2 is parallel to the outer housing surface 54a.
However, the stator blade 80 is shown as being rotated about the
centerline axis Z2 such that the blade 80 can more adequately form
an air straightening function with the leading edge 81 being
positioned to receive the rotating air at an angle and the trailing
edge 82 being aligned with the desired direction of the leaving
airflow, which is aligned with the longitudinal axis X of the fan
assembly 10. Referring to FIG. 19, the blade 80 is rotated about
the Z2 axis to create an angle .alpha.7 with respect to plane
defined with the outer surface 54a which coincides with the
longitudinal axis X of the fan assembly 10. As shown, .alpha.7 is
about 14 degrees although many other specific orientations are
possible.
[0100] In order for the first end 83 of the stator blade 80 to be
mounted flush to the inner housing outer surface 54a, meaning that
generally no significant gaps are present between the blade
material at the first end 83 and the housing outer surface 54a, the
first end 83 must match the blade interface projection contour 58.
As the stator blade 80 is formed from an extrusion, as opposed to
being formed in a casting process, the first end 83 must be cut to
match the projection contour 58. Where the outer surface 54a has a
cylindrical shape and the blade first end 206 has a double-wall
airfoil shape, as shown, the resulting cut required to match the
projection contour 58 must be a compound cut that is curved in one
direction and linear or straight in another direction. For example,
FIG. 20-23 show a slightly curved cut from the leading edge 81 to
the trailing edge 82 of the blade 80 and a generally linear cut
from the top surface 85 to the bottom surface 86 of the blade
80.
[0101] The second end 84 of the stator blade 80 must also be cut in
order to match the inside surface of the fan housing 20. In the
same manner that a projection contour 58 can be defined at the
inner housing outer surface 54a, a three-dimensional blade
interface contour projection 55 can be defined at the inner surface
20b. Accordingly, the description of the concepts regarding the
shape and formation of the cut at the first end 83 is equally
applicable to, and hereby incorporated by reference into, the
description for the shape and formation of the cut at the second
end 84. Accordingly, where the blade second end 84 has a
double-wall airfoil shape, the resulting cut required to match the
projection contour at the fan housing inner surface 20b must be a
compound cut that is curved in one direction and straight in
another direction, as shown at FIGS. 34-37.
[0102] Once each blade 80 has been cut at the first and second ends
83, 84, the blades 70 can then be attached to the inner and outer
housings 54, 20. In one embodiment, the housings 20, 54 and the
blades 80 are metal, such as aluminum.
[0103] Referring to FIG. 39, it is shown that the power wiring 61
for the stator assembly 50 can be routed through the internal
cavities 87a, 87b of one of the stator blades 80 such that a
conduit extending between the inner housing 54 and the outer
housing 20 is not required. This arrangement can result in a fan
efficiency gain, for example an efficiency gain of about two
percentage points. As shown, the inner housing 54 is provided with
an aperture 54c that is aligned with the internal cavity 87a and/or
87b. The outer housing 20 is also provided with an aperture 20c
that is aligned with the internal cavity 214a as well.
Axial Flow Fan Assemblies
General Description
[0104] Referring to FIGS. 40 and 41, a second embodiment 10' and
third embodiment 10'' of fan assemblies, respectively, are shown
that include axial-flow type fan wheels instead of mixed-flow type
fan wheels. The axial-flow fan wheels are discussed in further
detail in the following sections. It is noted that both fan
assemblies 10', 10'' are shown as including the same general stator
assembly 50 design that is shown for the first fan assembly
embodiment 10. As many of the concepts and features are similar to
the first stator assembly embodiment 50 shown in FIGS. 1 and 30-39,
the applicable description for the embodiments of FIGS. 40-41 is
hereby incorporated by reference for the second and third
embodiments.
[0105] Referring to FIG. 40, an axial flow fan assembly 10' is
provided in which a variable pitch axial fan wheel 440 is provided
instead of a mixed flow type fan assembly 40. In this embodiment, a
guide plate 59 is provided that is mountable to the stator assembly
50 to ensure that airflow is directed through the stator blades 80
instead of within the inner housing 54. As shown, the guide plate
59 is formed as a solid disk with a central opening 59a to allow
the motor shaft 62 to pass through and connect to the central hub
or connection mechanism 446. The guide plate 59 is also shown as
including a plurality of openings 59b that are configured to align
with the mounting holes 52a on the flange 52 such that the guide
plate 59 can be secured by the same fasteners (or additional
fasteners that are attached to the motor mounting plate) that
secure the motor 60 to the stator 50. In the embodiment shown,
guide plate 59 is formed from a galvanized material, although other
materials may be used. Once installed, the guide plate 59 functions
to block the majority of the airflow generated by the fan 440
through the central opening of the stator assembly inner housing
54. As such, the airflow stream generated by the fan wheel 40 is
instead directed past the stator blades 80. Referring to FIG. 41,
it is noted that the stator assembly 50 shown in FIG. 5 is provided
with only five stator blades 80 rather than the thirteen blades
shown in FIG. 40.
Axial Flow Fan Wheel Assemblies
[0106] As stated above, the axial fan assembly 10'' shown in FIG.
41 includes an axial type fan assembly 540. The primary differences
between fan wheels 40 and 540 are that the blades 570 are oriented
such that an axial flow pattern can be achieved rather than a mixed
flow pattern, and that the second end 573 of the blades 570 are
free rather than being attached to a wheel cone. As many of the
concepts and features are similar to the first to fourth
embodiments shown in FIGS. 1-28, the description for the first to
fourth embodiments, and all other embodiments presented herein
relating to fan wheels, is hereby incorporated by reference for the
sixth embodiment 540. Where like or similar features or elements
are shown, corresponding or like reference numbers will be used
where possible (e.g. 570 instead of 70).
[0107] Fan wheel 540 is similar to fan wheel 40 in that a
dome-shaped base, such as a wheel hub 542, is utilized, and in that
the same extruded aluminum profile for blade 70 can be used for the
fan wheel blade 570. Thus, the description of the fan blade 570
will be limited to the differences in how the ends are cut.
[0108] Referring to FIGS. 42-56, the fan wheel assembly 540 is
provided with a wheel hub 542 and six fan blades 570. It is noted
that the fan assembly 10''' shown at FIG. 26 shows a fan wheel with
four blades 570. Thus, it should be appreciated that fan assembly
40''' may be provided with any number of desired fan blades 570.
Referring to FIGS. 35-38, an example fan blade 570 is shown in
greater detail.
[0109] When a fan blade 570 is positioned and oriented as desired
with respect to wheel back 42, a three-dimensional fan blade
interface contour projection 548 can be defined on the outer
surface 42a of the wheel hub 42. An example contour projection 48
for one of the blades 570 is shown at FIGS. 47-49. The fan blade
orientation is defined by the rotation of the fan blade 570 about
the blade's 570 longitudinal axis L3, transverse axis T3, and
centerline axis Z3 with respect to the wheel back 542, shown at
FIG. 35. The rotation of the blade about the longitudinal axis L'''
operates to define an angle .alpha.4''', such as a blade pitch
angle of about 45 degrees, as shown at FIG. 33 (or anywhere between
5 degrees to 45 degrees at the tip). In the embodiment shown, the
blade 570 is also oriented such that the trailing edge 572 of the
blade 570 is generally parallel to the base portion 42c''' of the
hub 542 such that the longitudinal axis L''' is generally
orthogonal to the centerline X of the hub 542 and the fan assembly
542.
[0110] In order for the first end 573 of the blade 570 to be
mounted flush to the hub outer surface 542a, meaning that generally
no significant gaps are present between the blade material at the
first end 573 and the hub outer surface 542a, the first end 573
must match the blade interface projection contour 548. As the blade
570 is formed from an extrusion, as opposed to being formed in a
casting process, the first end 573 must be cut to match the
projection contour 548. Where the outer surface 542a has a
domed-shape and the blade first end 573 has a double-wall airfoil
shape, as shown, the resulting cut required to match the projection
contour 58 must be a compound cut that is curved in one direction
and linear or straight in another direction. For example, FIGS.
35-38 show a heavily curved cut from the leading edge 571 to the
trailing edge 572 of the blade 570 and a generally linear cut from
the top surface 575 to the bottom surface 576 to the blade 570.
[0111] The second end 574 of the blade 70 must also be cut in order
to match the inside surface of the fan housing 20 with a small
clearance, or at least be cut short enough to not touch the fan
housing inner surface 20b. Accordingly, the blade second end 574
can be cut to match the radius of the fan housing inner surface 20b
by implementing a compound cut that is curved in one direction and
straight in another direction, as shown at FIGS. 53-56. In one
embodiment, the second ends 574 of the blades 570 are cut such that
a clearance of about 1 millimeter to about 3 millimeters results
between the second ends 574 and the interior surface of the outer
housing 20. As stated previously, in one embodiment, the housing 20
is welded at a seam line 26 by a plasma arc welding process which
enables tight clearances between the fan blade ends 574 and the
housing 20 because a very low degree of deformation in the
roundness of the housing 20 occurs.
[0112] Once each blade 570 has been cut at the first and second
ends 573, 574, the blades 570 can then be attached to the wheel hub
542. In one embodiment, the wheel hub 542 and blades 570 are metal,
such as aluminum, and joined together by a welding process. Other
materials and joining methods may be used without departing from
the concepts presented herein.
[0113] Referring to FIGS. 50-52, the blades 570 can be plastically
deformed to achieve a desired twist angle, depending on the desired
flow/speed combination required. Once twisted the blades 570 could
be trimmed (using a milling machine or a fixture with a band saw)
to the proper angle and length. It is noted that the blades could
be trimmed in the same manner even if not twisted. The entire
assembly can then be tempered, as described further in the next
section. Referring to FIG. 52, the blades 570 are shown as being
twisted about longitudinal axis L3 by an angle .alpha.8'. In one
embodiment, the angle .alpha.8' is from about 20 degrees to about
45 degrees. In one embodiment, the angle .alpha.8' is about 30
degrees. It is noted that in the embodiment shown in FIGS. 50-52,
the blades 570 are not provided with a taper or cut near their
second ends 574. As is the case with the mixed-flow fan wheel with
twisted blades, an increase in efficiency can be attained in the
axial fan wheel 540 when the blades are deformed to have a
twist.
Methods of Producing a Fan Wheel
[0114] Referring to FIGS. 58-61, various processes are described
for the creation of fan wheels, fan assemblies, and stator
assemblies, as discussed in the following paragraphs. It is noted
that although the figures diagrammatically show steps in a
particular order, the described procedures are not necessarily
intended to be limited to being performed in the shown order.
Rather at least some of the shown steps may be performed in an
overlapping manner, in a different order and/or simultaneously.
[0115] Referring to FIG. 57, a flow chart illustrating a process
1000 for creating a fan wheel and/or stator is shown. In a step
1002, a base, such as a fan wheel back or hub having a domed or
conical shape, is provided. In a step 1004 a plurality of extruded
aluminum double wall fan blades having at least one internal hollow
cavity is provided. In one In a step 1006, a mounting position and
orientation for each of the plurality of fan blades onto the hub or
wheel back is determined. In a step 1008, a cutting profile for
each of the fan blades corresponding to its mounting location and
orientation on the base is determined. As stated above, the cutting
profile can correspond to a blade projection interface contour with
respect to the hub or wheel cone. In a step 1010, each of the blade
ends is machine cut to produce the desired cutting profile.
Subsequently, the blades are then mounted to the corresponding
mounting location used to identify the blade projection interface
contour at a step 1012. In a step 1014, each of the blades is
plastically deformed to have a twist about the longitudinal axis of
the blade. In one embodiment, the free ends of the blades are
twisted about a longitudinal axis that is about 20 degrees to about
45 degrees with respect to the end attached to the hub or wheel
back. In a step 1016, the free ends of each of the blades are cut
while the hub or wheel back is rotated about a central axis. In one
approach, the blades are cut with a cutting tool, such as a band
saw, that is parallel to the central axis, such as can be the case
with an axial-flow type fan wheel. In another approach, the cutting
tool is at an angle to central axis such that the free ends are cut
to match the angle of the wheel cone, such as may be the case with
a mixed-flow type fan wheel. When the cutting tool is parallel to
the central axis, step 1016 results in every part of the free end
of each blade to have the same distance from the center axis of the
hub or wheel back. Where a mixed-flow fan wheel is being produced,
the free ends of the blades can be attached to a wheel cone at a
step 1018, for example by welding. In a step 1020, the assembled
fan wheel can be subjected to a tempering process, such as heating,
cooling, hot working, cold working, naturally aging, artificially
aging, stretching, and/or stretching to increase the strength of
the material. In one embodiment, the components are subjected to a
tempering process to result in a temper designation of T5 while in
another embodiment, tempered to a T6 temper designation, for
example to result in 6063-T5, 6063-T6, 60161-T5, or 6061-T6
aluminum.
[0116] Referring to FIG. 58, a method 1100 is shown describing a
process by which the housing 20 of the fan assembly may be
produced. In a first step 1102, a sheet of material, such as an
aluminum or steel sheet is provided wherein the sheet has a first
end and a second opposite end. In a step 1104, the sheet of
material is rolled to have a cylindrical shape between the flanges
such that the first and second ends form a seam line. In a step
1106, the first and second ends of the sheet are joined at the seam
line with a welding process, such as a plasma arc welding process
to provide a fan assembly housing. Once the ends are joined to form
a tube, a flange is added on one or both ends of the tube by
expanding the tube to the desired inner diameter and forming the
flanges on each end at step 1108.
[0117] Referring to FIG. 59, a method 1200 is shown describing a
process by which the inner housing 54 of the stator assembly 50 may
be produced. In a first step 1202, a sheet of material, such as an
aluminum or steel sheet is provided wherein the sheet has a first
end and a second opposite end. In a step 1204, the sheet of
material is rolled to have a cylindrical shape. In a step 1206, the
first and second ends of the sheet are joined at the seam line with
a welding process, such as a plasma arc welding process to provide
a fan assembly housing. In step 1208 a plate is added to one end of
the cylinder by welding or fastening (or a combination of the two)
to create the motor mount plate.
[0118] Referring to FIG. 60, a method 1300 is shown describing a
process by which the stator assembly 50 may be produced. In a first
step 1302, a stator housing having a generally cylindrical shape,
such as the housing formed at process 1100, is provided. In a step
1304 a plurality of extruded aluminum double wall fan blades having
at least one internal hollow cavity is provided. In a step 1306, a
mounting position and orientation for each of the plurality of fan
blades onto the stator housing is determined. In a step 1308, a
cutting profile for each of the fan blades corresponding to its
mounting location and orientation on the hub is determined. As
stated above, the cutting profile can correspond to a blade
projection interface contour with respect to the outer surface of
the stator. In a step 1310, each of the blade ends is machine cut
to produce the desired cutting profile. Steps 1312 and 1314 are
similar to steps 1308 and 1310, except for that the opposite end of
the stator blade is cut to match the inner surface of the fan
assembly housing. Subsequently, the blades are then mounted to the
corresponding mounting location used to identify the blade
projection interface contour at a step 1316. In a step 1318, the
blades are also secured to the fan assembly housing. As stated
previously, the stator blades can be mounted to the stator housing
and the fan assembly housing with mechanical fasteners that engage
with anchor cavities 89 in the blades 80.
[0119] At step 1320, a motor may be mounted and secured to the
stator assembly. At step 1322, electrical lines can be routed from
the motor to the exterior of the fan assembly housing through at
least one internal hollow cavity of one or more of the stator
blades. As stated previously, the stator housing 54 may be provided
with an aperture 54c, which may be made before or after step 1206
and the fan assembly housing 20 may be provided with an aperture
20c, which may be made before or after step 1106.
[0120] Referring to FIG. 61, a method 1400 is described for making
mixed flow fan assembly having an inlet structure and a mixed-flow
type fan wheel. In a step 1402, a mixed-flow fan wheel having fan
blades with one free end and one opposite end mounted to a wheel
back. In a step 1404, an inlet structure defining a bell inlet
portion and a wheel cone portion is provided. In a step 1406, the
fan wheel is mounted to a motor shaft disposed within a fan
assembly housing while in a step 1408, the inlet structure is
mounted to the fan assembly housing. In a step 1410, the wheel cone
portion of the inlet structure is aligned with the fee ends of the
fan blades along a common central axis of the inlet structure and
the fan wheel. In a step 1412, the wheel cone is spaced from the
free ends of the fan blades to achieve a predetermined axial
distance along the central axis such that a gap is formed between
the free ends and the interior surface of the wheel cone.
[0121] The above described fan assemblies, fan wheels, stator
assemblies, and related methods have been determined, in some
embodiments, to result in a 20% increase in operational efficiency
while reducing manufacturing and material costs by up to 75%.
Accordingly, the disclosure represents a significant improvement
over the state of the art.
[0122] The various embodiments described above are provided by way
of illustration only and should not be construed to limit the
claims attached hereto. Those skilled in the art will readily
recognize various modifications and changes that may be made
without following the example embodiments and applications
illustrated and described herein, and without departing from the
true spirit and scope of the disclosure.
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